ARIA Accessibility Checker: Catch Missing Labels and Broken ARIA Before You Ship

Accessibility bugs are quiet. A missing label on an input, a typo in aria-labelledby, an unlabeled landmark — none of them break the page visually, and all of them break the page for screen reader users. The ARIA Accessibility Checker is a free, browser-based scanner that finds these problems in seconds.

You paste HTML, and the tool immediately runs 14 audit rules covering accessible names, ARIA attributes, roles, and landmarks. Results update live as you type, every issue is pinned to an exact line and column, and a one-click report summarizes errors, warnings, and passes in plain text.

Everything runs 100% client-side. Your markup never leaves the browser — which matters when you're auditing internal dashboards, customer templates, or anything else you'd rather not paste into a random web service.

Why Use the ARIA Accessibility Checker?

• Instant feedback loop. There is no "Run scan" button to hunt for. The moment you paste or edit markup, the findings list refreshes. Fix an issue, and it disappears from the list before you've finished typing the next line.
• Precise locations, not vague warnings. Each finding reports line:column plus the offending element snippet, so you can jump straight to the problem instead of re-reading the whole template.
• 14 rules that mirror real screen reader pain. The checks target the failures that actually hurt assistive technology users: missing accessible names on form controls, broken ID references, invalid roles, focusable elements hidden with aria-hidden, and more.
• Severity you can triage. Findings are split into errors (real barriers), warnings (risks and code smells), and passes — so you know what must be fixed versus what should be.
• Zero friction. No account, no upload, no install. A built-in sample document lets you see every check fire on deliberately broken markup, which makes the tool a learning device as much as an auditor.
• Privacy by design. Because the scanner is pure client-side JavaScript, it works for proprietary HTML that policy says you can't paste into third-party services.

Key Features

A few details worth knowing. The attribute validation checks against the full ARIA 1.2 attribute set, so a plausible-but-invented attribute like aria-name gets flagged as an error. Role validation covers roughly 70 standard WAI-ARIA roles — typos like role="buton" or retired roles surface instantly.

The reference checks are where the tool quietly saves hours: aria-labelledby, aria-describedby, aria-controls, and aria-owns are cross-checked against the IDs that actually exist in your markup. A dangling reference after a refactor — one of the most common ARIA regressions — is caught before it ever reaches a screen reader user.

How to Use

1. Open the ARIA Accessibility Checker.
2. Paste your HTML into the input panel — a full document, a component, or a fragment. Or press the sample button to load the built-in broken demo first.
3. Read the findings list. Errors (red) are genuine barriers; warnings (yellow) are risks worth reviewing; each item shows its rule, line:column, and the element snippet.
4. Fix the issues in your real source (or iterate directly in the tool) and watch findings drop off the list as you type.
5. When the scan is clean, click Copy report to archive a plain-text accessibility report for your PR description, ticket, or compliance notes.

Understanding ARIA, Roles, and Landmarks

Accessible names are the backbone. Every interactive control — button, link, input, select — needs a name that assistive technology can announce. The name can come from inner text (<button>Save</button>), a linked <label for>, an aria-label, or aria-labelledby pointing at readable text. The checker walks these sources for every form control and flags the ones that end up nameless. A button that renders as a bare icon is the classic failure:

<!-- Broken: no accessible name -->
<button class="icon-btn">
  <svg>...</svg>
</button>

<!-- Fixed -->
<button class="icon-btn" aria-label="Close dialog">
  <svg>...</svg>
</button>

Reference attributes are contracts. aria-labelledby="user-name" promises the browser that an element with id="user-name" exists. When IDs get renamed or a component is copy-pasted without its label, the contract breaks and the element loses its name at runtime — silently. The checker resolves every reference against the IDs present in your markup and warns about any dangling ones, including duplicate IDs that make references ambiguous.

Roles need to be valid — and backed by behavior. The checker validates role values against the standard role set, but it also catches a subtler trap: role="button" on a <div> without a tabindex can't receive keyboard focus, so keyboard users literally cannot reach it. That pairing gets a warning. Similarly, aria-hidden="true" on a focusable element is an error — you've told screen readers to ignore something the keyboard can still tab into, which is worse than either state alone.

Landmarks are the page's table of contents. Screen reader users navigate by regions: main, navigation, banner, contentinfo, form, search. The checker requires exactly one main, warns when repeated landmarks (two navs, for instance) lack accessible names to tell them apart, and reminds you to declare lang on the <html> element so synthesizers pick the right pronunciation.

Practical Use Cases

The pre-PR self-check

Before opening a pull request, paste the rendered component markup into the checker. Thirty seconds later you know whether the new feature ships with names on its controls and valid ARIA — accessibility review becomes a habit instead of a quarterly audit.

Auditing a component library

Run each component's markup through the tool and record the findings per component. Because the copyable report includes severity counts, you get a lightweight a11y scorecard you can track over time and cite in documentation.

Reviewing templates and email HTML

Newsletters, CMS themes, and legacy page templates rarely get accessibility attention. Pasting them in typically surfaces missing alt, unlabeled repeated landmarks, and inputs without names — a prioritized fix list for markup nobody wants to read line by line.

Learning and teaching a11y

Load the built-in sample and break things on purpose. Delete an aria-label, mistype a role, orphan a label for. Seeing the corresponding finding appear (with its line number) builds the mental model faster than any checklist, and it makes the tool a great live-demo companion for workshops.

Best Practices

• Prefer native elements over ARIA. A real <button> gives you focus, keyboard activation, and a name for free; role="button" on a <div> makes you responsible for all three.
• Never remove the only name. Refactoring inner text into an icon? Add aria-label in the same commit — the checker's live findings make this a two-second habit.
• Treat warnings as future errors. A positive tabindex or a role="button" div "works" today; both are regressions waiting for a keyboard-only user.
• Name your repeated landmarks. Two <nav> elements should be aria-label="Main" and aria-label="Footer" so users can tell them apart in the landmarks list.
• Fix duplicate IDs before fixing references. A labelledby pointing at two identical IDs is undefined behavior; dedupe first, then re-scan.
• Keep lang on <html>. It's one attribute, and it drives screen reader pronunciation for the entire page.

Start Scanning Your HTML

Accessibility failures in ARIA are invisible in a browser window and obvious in a screen reader. The ARIA Accessibility Checker closes that gap: paste markup, see the exact line and column of every missing name, invalid attribute, and broken reference, fix, and re-scan in real time. No account, no upload, nothing to install — just cleaner, more inclusive HTML before it ships.

Related Tools You Might Like:

• HTML Alt Text Checker — scan images for missing, empty, or broken alt attributes
• Heading Structure Checker — validate your H1–H6 outline for screen reader navigation
• Accessible Name Calculator — see exactly what name assistive technology will compute for an element

Happy auditing!